US1817067A - Drill stem - Google Patents

Description

ilatenteti Aug. 4, 1931 UNITED STATES ERD V. CROWELL, OF LOS ANGELES, CALIFORNIA DRILL STEM Application led February 2G, 1929.

This invention is a rotary drill stem for drill bits used in drilling oil wells and the like, and it is the object ot the avention to provide 'for normal positive rotation of the drill bit by a string of drill pipe, while permitting yielding of 'the rotary driving connection for relieving torsional strain when thetorqu-e ot the drill string reaches al predetermined maximum which has been calculated in accordance with a desired safety factor.

It is a it'urther object of the invention yto not only control the maximum torque of the drill string but also obstruct circulation when the predetermined maximum is reached, so as to indicate such condition by the reduction in iiow of the circulating medium and thereby provide a safety device forfboth regulating and indicating excessive torque.

More particularly the invention provides a threaded engagement between the drill pipe and the bit, with tensioning means normally preventing relative axial movement at the threaded engagementand thus holding the parts against relative rotation for maintaining al positive rotary drive, and the tensionino means adapted to yield responsive to a predetermined maximum torsional strain at the threaded engagement so as to permit relative threaded movement of the parts resulting in their relative rotation causing lag of the bit with relation to the drill pipe, with the pitch of the threaded engagement calculated with relation to the tensioning means so as to hold the parts against their relative threaded movement and thus maintain the positive rotary drive until the to-rque reaches the maximum which has been determined as the limit of safety.

It is a further particular object of the invention to provide the drill stem with a normally open valve permitting usual circulation of a fluid as long ask the positive rotary drive is maintained, but adapted to at least partially shut-olf circulation when there is Serial No. 342,896.

relative threaded movement between the drill pipe and the bit as a result of excessive torsional strain, in order to indicate by the resulting partial stoppage of circulation that the predetermined maximum torque has been reached.

Further objects of the invention will be readily understood from the following description of the accompanying drawings, in which:

Fig. l is a front elevation of the drill stem partly in axial section and transversely severed at the line A-A, showing the normal positive rotary drive for the bit.

Fig. 2 is a 'fragmentary axial section through the drill stem, showing the bit. lagging vvith relation to the drill pipe in accordance with excessive torque.

Figs. 3, 4, 5 and (i are transverse sections on the correspondingly indicated lines of Fig. l.

The drill stem is adapted for suspension from a usual string ot' rotary drill pipe l, and preferably comprises a tubular body 2 having an extension 2 adapted to receive a bearing projection 3 et a. collar 3 trom which a usual drill bit Ll is suspended. A sleeve 5 is axially slidable in the extension 2 but turns therewith so that it is rotated by the string of drill pipe l, and a threaded engagement is provided bet veen this rotat- 7 ing sleeve and a mandrel 7 with which the collar 3 and the drill bit 4: are adapted to turn. A spring 8 normally holds the rotating sleeve retracted against threaded elevation relative to mandrel y7 as shown in Fig. l, so that the threaded engagement turns the mandrel with the rotating sleeve in order to provide a positive rotary drive for the drill bit l5 but when the torque of the drill string reaches a predetermined maximum the spring 8 is adapted to yield so as to permit threaded movement of rotating sleeve 5 upwardly along mandrel 7 as shown in Fig. 2, thereby causing rotary lag oi the mandrel with relation to the sleeve 5 resulting in corresponding yielding of the rotary driving connection for the drill bit.

Circulation through the drill string is preferably by way of a pipe 9 which is adapted for axial movement with sleeve 5, :and a valve l may be suspended in body 2 so that during normal threaded retraction of the sleeve on mandrel 7 for maintaining the positive rotary drive, the valve l0 is spaced from the open end of pipe 9 as shown in Fig.

l in order to permit unobstructed circula-` tion; while threaded elevation of sleeve 5 on the mandrel'as a result of theY torque -of the drill string overcoming the tension of spring 8, will correspondingly elevate ypipe 9 relative to valve l() as shown in Fig. 2 so that the valve seats in the open end of the pipe and thus at least partially obstructs circulation for indicating that th'eV positive rotary .drive for the drill bit has yielded responsive to a predetermined maximum torque.,4 v A is an instanceof ther aforementioned arrangement of pa-rts,'tlie body 2 may be suspended'from drill pipe l by ausual threaded connection l2, and a guide pipe'l open-at its upper end to the bore le of pipe l is preferablyV suspended in body 2 by a threaded connection l5. The pipe 9 is adapted for telescopic reception in guidepipel, with packing 1G between pipe 9 and the bore of body 2 preferably `compressed by the guide pipe against a shoulder l? in the bore of body 2 sov as to insure Aall of the circulating medium flowing downwardly through pipe 13 and thence through pipe 9. A rthe 'valve lO 'which cooperates with th open nd of pipe k9 is shown as a'usual tapern ing valve, preferably having hyp-passes 18 for permitting some flow of the circulating medium past the valve even when the valve isV seated for shuttingoll' themajor portion of the flow; and the valve is preferably suspended from a stem 19 which may slidably project through a spider 29 mounted in pipe i3, with downwardmovement ofthe valve stein limited by its head 2l Vengaging the spiderwhich lis shown as cutaway to form suitable passages 22 for free flow of thecirculating fluid.

'llhe pipe V9 may be arranged for axial movement with sleeve 5 by threading the lower end rof the pipe into the closed upper end of a tube 25V which may bein turn threaded into a coupling collar 2G at the Lipper end of slee-ve 5; and theY spring S, which ispref# Lerably a.' relatively heavy coil spring, prefervided with grooves or'lreyways 3l adapted to lengage lcorresponding' longitudinal lugs 32 on the outer surface of sleeve 5 for rotat- Ying the sleeve with the body while pei-initra pipe 35 preferably projecting upwardly from said open bore and telescoping in pipe 9, andthe pipe may be provided with a packing ring 36 engaging the bore of pipe 9 for insuring` all of the circulating medium `flowing .downwardly through the bore of the mandrel. The collar 3 and its bearing proj ection 3 is provided'with a bore 87 communicating with the vbore of themandrel and opening 'into the usual circulating bore 38 of drill bit el for circulating a fluid in usual manner during the drillingoperation.

The threaded engagement between rotating sleeve 5 and the mandrel 7 preferably comprises threads ll() of extremely coarse pitch on the exterior surface of the mandrel engaging corresponding vthreads il in the bore of sleeve 5; and the tension of spring 8 is such with relation to the pitch of threads ,l0-ll as to normally hold the Vrrotating sleeve retracted on the mandrel against threaded elevation relative thereto so that the mandrel is positively rotated with the sleeve as shown in ll ig. l, but the spring is adapted to yield responsive tol a predetermined maximum torsional strainy yat the threaded Aengagement lll-ll so'asfto permit threadedelevation of the rotating sleeve relative tothe mand-rel and thus causecorresponding rotary of the mandrel with relation y to Vthe rotating sleeve as shownv in Fig. 2. This rotary lag of the mandrel results in corresponding rotary lag of drill bitl relative to the string of rotary drill pipe l, since the sleeve 5 is rotated by the extension 2EL of the tubular body 2 which is in turn rotated by drill pipell, while the mandrel 7 is fixed for rotation with the bearing projection Stof the collar 3 from which the drill bit l is suspended; and consequently by providing any predetermined i relationship between Athe tension of spring 8 and the pitch of threads 404-41-, the drill bit l will be rotated with the drillpipe 1 as long as the torque ofthe drill vstringdoes not exceeded the predetermined 'maximuim but torque beyond said predetermined safety factor will cause the bit to lag relativeto the rotating dri-llV pipe in order to relievertheexcessive torque.

The bearing projection 3a of collar 3 which supports t'he'jdrill bit is preferably ournaled in a bearing sleeve 45 which may be fixed to the lower end of body extension '2a by means 'llO of a usual threaded connection 46, and a collar 47 is preferably threaded onto the upper end of the bearing projection 3u and rotatably seats on a shoulder 48 formed by the upper end of bearing sleeve so as to prevent axial displacement of collar 3 while permitting its rotation relative to the string of drill pipe for producing the desired rotary lag of the bit when t-he predetermined maximum torque is reached. A thrust bearing comprising an annulus 49 may be provided between the bearing projection 3a and the bearing sleeve 45, and packing shown at 50 is preferably also provided between these relatively rotating parts. The packing 50 in conjunction with the packing 16 and 36 thus packs-off the bore for the circulating medium which extends through the drill stem, so that the threaded engagement 40-41 is shut-off from said circulating medium both above and below said threaded engagement, and the possibility of mud or the like clogging the threads is thus avoided and a suitable lubricant sealed against escape by the packing may be provided at the threaded engagement.

Arcuate abutments 51-52I preferably project axially'from the proximate ends of bearing sleeve 45 and collar 3, and are adapted for circumferential abutment to preferably limit the relative lag of drill bit 4 to approximately one-half a revolution as will be understood by a comparison of Figs. 1 and 2; and an annular groove 53 is preferably provided in the end of collar 3 for reception of an axially projecting tongue 54 on the abutment 51 so as to maintain concentric alinement of the abutments during relative rotation of bearing sleeve 45 and collar 3.

1n operation the parts are normally in the position shown in Fig. 1, with spring 8 holding the sleeve 5 in axially depressed position relative to mandrel 7 and against threaded elevation on the mandrel, so that the valve 10 is spaced from the end of pipe 9 for free circulation through the drill stem. and the arcuate abutment 51 of bearing sleeve 45 is in advance of the cooperating abutment 52 of collar 3. The tension of spring` 8 thus holds the drill bit against rotary lag relative to the string of drill pipe as long as the torque of the drill string does not exceed a predetermined maximum; but when the torque exceeds the predetermined safety factor the torsional 'strain at threads 40-41 overcomes the tension of spring 8 and permits threaded elevation of sleeve 5 relative to mandrel 7. Rotation of drill pipe 1 is thus continued with the drill bit lagging behind. to the limit of movement permitted by the abutment of the cocirculation advises the operator thatl the torque of the drill string has reached the predetermined maximum, and at the same time the torque is relieved by the lagging of the drill bit relative to the rotating drill pipe.

I have thus provided extremely simple but practical means for regulating the torque of a drill string by a driving connection which is adapted to permit rotary lagging of the drill bit when the torque reaches a predetermined maximum, and said yielding of the rotary driving connection is also adapted to at least partially shut-off circulation for indicating that the torque has reached the predetermined limit of safety.

I claim:

1. A drill stom comprising a body adapted by a string of drill pipe, a section fixed against axial displacement relative to the body and adapted to rotate a drill bit, and a normally non-yielding rotary driving connection between the body and said section adapted to rotatably yield in accordance with a predetermined torque of the drill stem so as to permit rotary lagging of the drill bit with relation to the string of drill pipe.

2. A drill stem comprising relatively rotatable sections, one of which is adapted for rotation by a string of drill pipe and the other of which is adapted to rotate a drill bit, a ff normally non-yielding rotary drivinj; connection between said sections adapted to rotatably yield in accordance with a predetermined torque of the drill stem so as to permit rotary lagging of the drill bit with relation to the string of drill pipe, and means for indicating said yielding of the rotary driving connection.

3. A drill stein having a circulating bore and comprising relatively rotatable sections, one of which is adapted for rotation by a string of drill pipe and the other of which is adapted to rotate a drill bit, a normally nonyielding rotary driving connection between said sections adapted to rotatably yield in accordance withpredetermined torque of the drill stem so as to permit rotary lagging of the drill bit with relation to the string of drill pipe, and means actuated by said yielding` of the rotary driving connection for retarding circulation through the said bore.

4. A drill stem having a circulating bore and comprising a body adapted for rotation by a string of drill pipe, a section fixed against axial displacement relative to the body and adapted to rotate a drill bit, a normally non- A yielding rotary driving connection between the body and said section adapted to rotatably yield in accordance with a predetermined torque of the drill stein so as to permit rotarv lagging of the drill bit with relation to the string of drill pipe, and fluid tight packing for packing-olf the rotary driving connection from the circulating bore.

5. A drill stem having a circulating bore f and comprisingrelatively rotatable sections,

Vone'of which Vis-ad'apted for yrotation by a string of' drill'pipe and the other ofv which isadapted to rotate a drill bit, a normally nonf yielding rotaryJ drivingconnection between said sections adapted to rotatably yield in accordance with a predetermined torque ofthe drillstem', means actuated by said yielding oi the rotary driving connection" for retard! ing circulation through .the said bore, andy means for ,packing-oil the rotary driving connection from the bore.

G. 'A drillstem comprising a body adapted for rotation'by a string of drillpipe, a section tixed against axialv displacement relative to the body and adapted to rotate a drill bit, a normally nonfyielding rotary' driving connection between the body and said section Y mined torque ofk the drill stem so as to permit being `v 60 rotary lagfring of the bit with relation to the stringy of drill pipe, cooperating abutment elements circumferentially lixed with relation to the respective sections and adapted for circumferential abutment for limiting said relative lag of the bit,'and an axially extending annular tongue and groove engagement between the abutment elements for maintain-` ing their concentric alinement.

8. A drill stem comprising relatively r0- tatable sections, a body adapted for rotation b* a string of drill aine and en aGinG one o l D b i the sections for rotating the same, the other of saidV sections being adapted for rotation ybut lixed'against axial displacement relative to the body and adapted to rotate a drill bit, anda normally non-yielding rotary driving connection between said sections adapted to rotatably yield in accordance with a predetermi ef torque of the drill stem so as topermit rotary` lagging of the drill bit with relation to the string of drill pipe. l

9; A drill stemfcomprising relatively ro'- tatable sections having a circulating bore, a ybody adapted'for rotation by a string oi" drill pipe and'engaging one of the sections for rotating the same, the other of said sections adapted for rotation but tixed against axial displacement relative to the body and adapted torotate a drillv bit, a normally non-yielding rotary driving connection between said sections adaptedtoro` tatably yield in accordance with a pred-etermined'torqueof the drill stem lso as to permitk connection.

rotary lagging of' the drillbit with relation to the spring of drill pipe, and packing between the body and the circulating bore of the sections forv packing-oill the rotary driving l0, Al drill` stemcomprising relatively rotatable sections, a; body adapted' for rotation by a string of drill pipe 'and engaging one of thev sections :tor rotatingfthe saine, the other of .said sections ,being adapted for rotation but ixed against axial displace`- ment relative to thel body and ladapted to rotate drill bit, a normally non-yielding rotary driving' connection betwen said sections adapted to rotatably yield inaccordance with a predetermined'torque of the drill stem so as to permit rotarylagging of said other section with relation to the body, and cooperating abutment elements Viixcd relative to the body and said other section and adaptedk 'for circumferential abutment Jfor limiting the relative lag of said other section.

l1. A drill stem comprisingrelatively rotatable sections, a body adapted for rotation by a string of drill pipe and engaging one of the sections for rotating the same while permitting axialv movement of said section relative ktothe kbody, saiov section constituting a drive section, the other otfsaid sections being lixed against axial displacement` relative to the body and adapted to rotate a drill bit, saidsection .constituting a driven section,.a threaded engagement between the sections, and means for normally tensioning .a

the drive section against axial movement relative to the body so as to hold the `sect-ions againstl relative `threaded movement and thus maintain a positive rotary .driving connection between the sections, the rsaid tensioningV means bcing adapted' to yield in accordance with a predetermined torque of the drill stem in order to permit axial movementl oi the drive section relative to the body for relative threaded movement between the sections causing yielding of the rotary driving connection and lagging of the bit with relation to the string ofv drill pipe. s

1Q. A drill stem comprising relatively rotatable sections having a circulating bore, a body adapt-ed for rotationl by a string of drill pipe and engaging one of thel sections for rotating the Vsame while permitting axial movement'o'f said section relative to the body, said section constituting aV drive section,'the other of said, sections being fixed against axial displacement relative tothe body andadapted to rotate a drill bit, said section constituting a drivenV section, means 1f! Vlor normally tensioning the drive section against axial movement relative to the body,

Va( driving connection between 'the sections heldf'against yielding by said non-movement of the drive section relative to the body, the

said tensioning means being adapted to yield in accordance with a predetermined torque of the drill stem in order to permit axial movement ot the drive section relative to the body, said movement of the drive section causing rotary yielding of the driving connection and lagging ot the drill bit with relation to the drill pipe, and a valve mounted in the body and normally spaced from the circulating bore or" the drive section so as to permit unobstructed circulation but arranged whereby axial movement of the drive section relative to the body in response to yielding of the tensioning means is adapted to seat the valve in the circulating bore of the drive section for obstructing circulation.

13. A drill stem comprising relatively rotatable sections having a circulating bore, a body adapted for rotation by a string of drill pipe and engaging one oi' the sections for rotating the same While permitting axial movement of said section relative to the body, said section constituting a drive section, the other of said sections being fixed against axial displacement relative to the body and adapted to rotate a drill bit, said section constituting a driven section, means for nor mally tensioning the drive section against axial movement relative to the body, a driving connection between the sections held against yielding by said non-movement ot' the drive section relative to the body, the said tensioning means being adapted to yield in accordance With a predetermined torque of the drill stem in order to permit axial movement of the drive section relative to the body, said movement of the drive section causing rotary yielding of the driving connection and lagging of the drill bit with relation to the drill pipe, a pipe projecting upwardly from the bore of the drive section, and packing between said pipe and the body.

14. A drill stein comprising relatively rotatable sections having a circulating bore, a body adapted for rotation by a string of drill pipe and engaging one of the sections for ro tating the same while permitting axial movement of said section relative to the body, said section constituting a drive section, the other oi said sections being iixed against axial displacement relative to the body and adapted to rotate drill bit, said section constituting a driven section, means lor normally tensioning the drive section against axial movement relative to the body, a driving connection between the sections held against yielding by said non-movement of the drive section relative to the body, the said tensioning means being adapted to yield in accordance with a predetermined torque of the drill stem in order to permit axial movement of the drive section relative to the body, said movement of the drive section causing rotary yielding of the driving connection and lagging of the pipe projecting upwardly from the bore of the drive section, a pipe projecting upwardly from the bore of the driven section and telescoping in the irst men tioncd pipe, and pack-` ing between said pipes.

l5. A drill stem comprising relatively rotatable sections having a circulating bore, a body adapted for rotation by a stringl ot dri-ll pipe and engaging one of the sections tor rotating the saine while permitting axial infwenienl. ci said section relative tothe body, said section constituting a drive section, the other said sections being adapted for rotation but lined against axial displacement reiative to the body and adapted to rotate a drill bit. a normally non-yielding rotary driving connection between said sections adapted to rotatably yield in accordance with a predetermined torque of the drill stem so as to permit rotary lagging of the drill bit with relation to the string ot drill pipe, the rotary driving connection being arranged whereby its yielding will axially shift the drive section relative to the body, and a valve mounted in the body and normally spaced from the circulating bore of the drive section so as to permit unobstructed circulation but arranged whereby said axial shifting et the drive section relative to the body is adapted to seat the valve in said circulating bore for obstructing circulation.

16. A drill stem comprising relatively rotatable sections having a circulating bore, a body adapted for rotation by a string of drill pipe and engaging one et the sections for rotating the same, the other ot said sections being adapted for rotation but fixed against axial displacement relative to the body and adapted to rotate a drill bit, a normally nonyielding rotary driving connection between said sections adapted to rotatably yield in accordance with a predetermined torque of the drill stein so as to permit rotary lagging oi the drill bit with relation to the string oi' drill pipe, and packing between the body and said sections axially beyond the rotary driving connection.

17. A drill stem comprising relative rotatable sections, one of which adapted for rotation 'by a string of drill pipe and the other of which is adapted to rotate a drill bit, a nor-- mally yielding rotary driving connection between said sections adapted to rotatably yield in accordance with a predetermined torque of the drill stem so as to permit rotary lagging of the bit with relation to tlie string ot drill pipe, cooperating abutment elements circumferentially fixed with relation to the respective sections and adapted for circumferential abutment tor limiting said relative lag of the 18. A drill stein comprising a body adapted for rotation by a string of drill pipe, a section fixed against axial displacement relative 6 s ,.81 "meer to the bodyy and adaptedv to rotate a drill bit, v

the body and said section having normally vcommunieating circulating bores, fluid tight packng'means ybetween the body and said section, and a normally non-yielding rotary driving connection between the' body and said section adapted'to rotatably yield in accordance' With a predetermined torque of the drill stem so as to permit rotary lagging of the drill bit with relation tothe string of drill pipe.

In testimony whereof he lhas affixed his signature. Y

ERD V. GROWELL.

CERTIFICATE 0F CORREC'UON.

Patent No. 1,817,067. Granted August 4, 1931, to

ERD V. CROWELL.

It is hereby certified thaterror appears in the printed specification of the above numbered patent requiring lcorrection as follows: Page 3, line 82, ciaim 1, after "adapted" insert for rotation; and that the said Letters Patent should be read with this correction therein that the same may conform to the record of the case in the Patent Office.

Signed and sealed this 29th day of September, A. D. 1931.

M. J. Moore, (Seal) Acting Commissioner of Patents.

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